These are some demos come from the book 「Cocoa Programming for Mac OS X」 , and I will add more here.

Maybe your first Cocoa Program, use it to understand the MVC structrue.

Another easy demo.

#SpeakLine An interesting demo to translate text to sound, and remember last voice you selected(by userDefault)

#DiceView An interesting demo teach me the way to create a custom userControl.

#NerdTabViewController A demo teach me how to create a Tab-style view

wait more to come~~